Emergency Power Supply (EPS)

Despite being told before ordering that my new solar and battery system would provide backup power in the event of a grid outage I found out the other day, during a grid outage, that it doesn't! On further investigation it would appear that it has been wired incorrectly so I contacted the installer, Octopus Energy, only to be told that they don't install systems with that feature enabled. They referred me to GivEnergy with the caveat that if anyone touches the system I'll lose the workmanship guarantee that they, Octopus Energy, provide.

So, the question is, how easy is it to enable the feature and what is involved. If Octopus Energy don't line up to resolving the issue I'd obviously use a GivEnergy approved installer to carry out the work.

ihunter What does your contract say?

The "feature" will require the physical installation of an earth spike so its not a trivial "flick a switch" sort of thing.

Edit - also I think you'll struggle to find anyone who is GE approved who would take on the job at this stage.

https://kb.givenergy.cloud/article.php?id=12&oid=1

Vestas Contract says nothing but it was discussed and I went for an extra battery to provide additional capacity to support the feature so there was no ambiguity. From then on I assumed it was part and parcel of the system and given that the house will run on batteries when grid power is available is it unreasonable for a layman to also assume it will run on batteries when there's a grid outage?

I'm guessing from your reply that it's a reasonably big job then, which all becomes a moot point if I can't get anyone to do it anyway. I've put in a complaint with Octopus Energy so will see what, if anything, happens with that first.

ihunter It all depends on what you want the EPS to do and how your existing house is wired up.

It sounds like you had an expectation that the EPS would provide power for most of the house in the event of a power outage. There are a couple of options for doing this, either automatic or manual switchover switch. One thing you have to ensure is that you don’t exceed the maximum inverter output and battery discharge rate when operating in EPS mode, so manual switches are often recommended for this so you can turn off any high load appliances before turning on EPS mode.

Anyway, it’s a fairly straight forward electrical job to potentially split your fusebox, install an automatic or manual changeover switch and to install the earth spike that as mentioned you’ll need. All of that has nothing whatsoever to do with the inverter, batteries and solar install that Octopus did for you.

Where the two come together though is that the changeover switch needs to be connected to the EPS output terminals of your inverter. There’s no reconfiguration of the inverter as they all come with EPS capability out of the box.

geoffreycoan You are correct, that was exactly my expectation. 🙂

Thanks for the explanation on what is required, it's not looking as daunting as I first feared. One last, maybe stupid, question. Can the earth spike be drilled and installed through my garage floor?

ihunter Can the earth spike be drilled and installed through my garage floor?

I'm not an electrician so treat my answer with appropriate scepticism!

The earth spike needs decent contact with the earth. On Tim & Kat's Green walk YouTube video where they walked through their EPS setup I am pretty sure that the earth spike was hammered into the garden and the earth cable was run along in a slit cut into the concrete along the front of their garage and then to the fusebox.
I'd guess that their electrician felt this would ensure that there was decent physical connection of the spike to the earth whereas if you drill through the garage floor you have no way of knowing what is underneath and whether the (dry?) earth is going to provide sufficient conductivity. You'll also puncture the plastic damp-proof membrane that's under the garage floor so could let damp in.

Its this kind of extra work is probably one reason why Octopus don't want to do it.

geoffreycoan All makes sense, thanks for your help.

If it helps, the earth rod for my AIO was drilled straight through the basement floor. My house is >100 years old so not really comparable to a garage, but still. The rod is around 1 metre long, and went vertically down - the biggest worries were (a) hitting a drain as there wasn't an accurate drawing of where they went, and (b) the resistance being too high. In the end, there was no drain there, and the resistance was absolutely fine (miles lower than the allowed amount).

For my AIO they ran the earth out of the garage, just the other side of the wall and put the rod down into the ground so it wasn’t foundations. Covered it in a little black box.

The rod really need to be in some earth where you are sure of decent contact (and earthing) >dry ground under a garage may not get the readings you need - not just at day 1 when you might wet the ground when drilling the garage floor but after it dries out. A rod outdoors in the ground gets rain on it. Best to ask an electrician.
Though screwing rods together and hammering down and down will get damp ground at some point, i think.

Slightly off topic but definitely related, if you have AIO and Gateway installed how do you know the gateway has functioned as it should during a power outage. We just had a power cut, everything went off for a split second, how do I know when grid is back on or even if it went off? I can see the battery and solar combining to satisfy my load, but know way of knowing if the grid is still out! Thought the app might tell me?.

Jase1703
I believe that the GE app shows the grid struck out if it is off

If you are running GivTCP or similar you should be able to see the grid frequency and voltage, which should be zeroed out in a fail. (And - for me at least - sometimes not in a fail.)

Been in touch with my local authorised GivEnergy installer and they're putting together a quote for me. Thanks everyone for your input.

Jase1703 Yes, if you use the GE app you see the grid icon grey with a line through it. If you use Inverter Monitor is displays the word OUTAGE.

ihunter Do bear in mind that because of the way the GE "ecosystem" works the "new" GE installer will now be responsible for the system, not Octopus. Basically the last GE installer who touches the system is responsible for any issues and also (potentially) dealing with GE and warranties.

Their quote will probably reflect that.

We had a EPS socket fitted to our Gen2 inverter. Our installer fitted a earth rod and connected a socket with RCD in the location we asked for.

I installed one earth rod adjacent to the outside wall of my house, where it is under a wheelie-bin. The resistance was a bit too high, better when I poured a jug of water over it. I installed a second earth rod adjacent to the garage wall, beside the rainwater drain, where the soil is and it was fine. This relies on the SWA cable from the house to the garage being connected, so I am entirely happy to have both.